Organisms that are ______ must obtain their oxygen from oxygen-containing compounds, while ________ need free atmospheric oxygen.

Prepare for the AAMI Microbiology exam for embalmers with our comprehensive quiz. Use flashcards and multiple-choice questions with explanations and hints to master exam content and enhance your study experience.

Oxygen use and source define how microbes generate energy. Aerobes rely on free atmospheric oxygen as the terminal electron acceptor in aerobic respiration, so they need oxygen readily available in the air to grow and function. Anaerobes, on the other hand, do not require atmospheric O2 and are often inhibited by it; they obtain the oxygen they need from the substrates they metabolize (the oxygen atoms contained in those molecules) rather than from the air, using fermentation or other electron acceptors instead of O2. This pairing fits the statement: anaerobes come from environments without needing atmospheric O2, while aerobes depend on it.